The present invention relates to a semiconductor integrated circuit having a non-volatile memory, an ink cartridge having the semiconductor integrated circuit, and an inkjet recording device having the ink cartridge attached.
In general, a semiconductor integrated circuit consumes electronic power as long as a power supply is supplied even when a predetermined operation is not performed. Thus, there is a need for suppressing the power consumption as much as possible in a stand-by condition where a predetermined operation is not operated. In order to address such a need, it may be possible to add a function for shifting operation modes from a general operation mode to a low power consumption operation mode (called stand-by mode, below) to a semiconductor integrated circuit. In this way, when adding the function for shifting to the stand-by mode, timing for switching modes is important. That is, shifting to the stand-by mode at an arbitrary time may have an influence on regular operations. Thus, it is necessary to switch modes at proper timing.
Further, in order to provide a semiconductor integrated circuit with the function for switching operation modes, it is necessary to provide a control terminal for receiving control signals for the operation mode shifting. Then, the operation modes can be changed to the stand-by mode by giving control signals at a predetermined electric potential level to a control terminal for operation mode switching.
By the way, when a plurality of semiconductor integrated circuits are used in one system, a select signal is required for selecting from among the plurality of semiconductor circuits. In this case, it is required to provide a device selector terminal for selecting each of a plurality of devices.
Furthermore, it is common to provide a control terminal for circuit block initialization in the semiconductor integrated circuit in order to obtain a function for initializing built-in circuit blocks. In addition, when the circuit blocks are initialized, an internal condition can be set at a predetermined value by supplying a control signal at a predetermined electric potential to the control terminal for circuit block initialization.
In the semiconductor integrated circuit, in order to realize the operation mode switching function and the circuit block initialization function, the control terminal for the above described function is provided as an independent external terminal along with external terminals of a semiconductor integrated circuit typically including a high potential power supply input terminal, low potential power supply input terminal, and a reference clock signal input terminal, for example.
However, the semiconductor integrated circuit having the above-described function for shifting to the stand-by mode, the device selecting function, and the circuit block initialization function must include each of a control terminal for memory initialization and a control terminal for operation mode switching. Thus, there have been problems as described below.
That is, an increase in a number of control terminals requires a space where terminals are provided on the outside of the semiconductor integrated circuit. As a result, it causes a problem that the chip size within the semiconductor integrated circuit is increased. In addition, the increase in the number of the control terminals means an increase in the number of signal external wiring for external chips communicating with the present chip, resulting in a problem of increased implementation costs.
Further, in order to realize each of the functions in the semiconductor integrated circuit, it is necessary to generate each of the control signals for input to the control terminal for circuit block initialization and the control signals for input to the control terminal for operation mode switching. Furthermore, since these control signals must be supplied at desired timing, there is a problem that control gets more complicated.
The present invention was made in order to overcome the above-described problems of the conventional technology. A purpose of the present invention is to provide a semiconductor integrated circuit, which allows switching of operation modes at proper timing and reduction of a number of external terminals.
A semiconductor integrated circuit according to the present invention has a low power consumption mode that is lower in power consumption than a regular operation mode performing a regular operation and is implemented in an ink cartridge. The semiconductor integrated circuit includes a control unit for controlling a shift to the low power consumption mode in response to an end of a printing operation using the ink cartridge. The semiconductor integrated circuit may further includes a storage unit for storing predetermined data at a specified address, and an address creating unit for sequentially creating addresses specified for the storage unit. In this case, the address is initialized when shifting to the low power consumption mode by the control unit.
Further, the operation of internal circuits including a sense amplifier for creating a signal for reading out data stored in the storage unit, an address decoder for specifying an address in the storage unit, a buffer used for reading out data read out from the storage unit, and a latch circuit for latching data read out from the storage unit may be terminated in the low power consumption mode shifted to by the control unit.
Another semiconductor integrated circuit according to the present invention may perform a shift to the low power consumption mode by the control unit and an initialization of address created by the address creating unit by means of a control signal input from a common external terminal. The common external terminal may be a chip-select terminal.
An ink cartridge according to the present invention has the above-described semiconductor integrated circuit for storing at least the remaining amount of ink.
An inkjet recording device according to the present invention has the above-described ink cartridge for printing desired image information by using ink supplied from the ink cartridge.